The 2007 Mazda MAZDA6 runs on regular unleaded.
They use xenon gas bulbs. These are a form of halogen lighting.
HID bulbs are primary use is for when you need high levels of light over large areas. These areas include gymnasiums, large public areas, warehouses, movie theaters and football stadiums.
If you're smart, you don't. "HID kits" are widely available, but they are (all) illegal and dangerous. The only legitimate/safe/legal HID conversion is to install complete HID headlamp assemblies designed, built, tested, and certified as such. Halogen headlamps must use halogen bulbs. If your headlamps have already had an "HID kit" installed, remove it and put the correct bulbs back in.
A ballast is a ballast in most cases. So yes you should be fine.
A Honda Civic coupe has 9003 headlight bulbs
If you're smart, you don't. "HID kits" are widely available, but they are (all) illegal and dangerous. The only legitimate/safe/legal HID conversion is to install complete HID headlamp assemblies designed, built, tested, and certified as such. Halogen headlamps must use halogen bulbs.
The 2006 Mazda MAZDA6 runs on regular unleaded.
The 2005 Mazda MAZDA6 runs on regular unleaded.
The 2004 Mazda MAZDA6 runs on regular unleaded.
The 2013 Mazda MAZDA6 runs on regular unleaded.
The 2009 Mazda MAZDA6 runs on regular unleaded.